| Bromate levels in today’s drinking water are considered a significant cancer risk; therefore, new regulatory limits have been set. The two major sources of bromates in drinking water are using ozonation and sodium hypochlorite solutions in the disinfection process. As of December 16, 2001, Stage 1 of the Disinfectants and Disinfection Byproducts Rule will require potable water treatment plants to meet a Maximum Contaminant Level (MCL) of 10 parts per billion in their treated discharge. Water treatment plants utilizing ozone will need to test their water monthly. Since sodium hypochlorite can be a source of bromates, plants using hypochlorite solutions are required to test using the ANSI/NSF Standard 60 and/or AWWA Standard for Hypochlorites.
Tests have demonstrated that bromine is higher in sodium hydroxide made with diaphragm cell technology and chlorine from membrane and mercury cell technology. This is further complicated because the level of bromine in these two materials is actually related to the bromide contamination of the salts used in the production process. Since chlorine and sodium hydroxide are used to manufacture sodium hypochlorite, the bromates are a result of the raw materials selected. Therefore, choosing specific suppliers and process technology for chlorine and sodium hydroxide will reduce the overall amount of bromates found in sodium hypochlorite.
NSF has approved the Two-Tiered Standard that provides two grades of Standard 60 certified sodium hypochlorite to operators of water treatment plants.
Low Bromate Hypochlorite Solution
Hypochlorite treatment chemicals shall not exceed 10% of the bromate MCL or contribute a bromate residual of 1 ppb or less to the “finished drinking water”. At the Maximum Use Level specified by NSF, the bromate in our finished products are estimated to be:
| |
Dixichlor
(Sodium Hypochlorite 10%) |
Dixichlor Max
(Sodium Hypochlorite 12.5%) |
| Maximum Use Level in Water |
105 mg/L |
84 mg/L |
| Bromate in Hypochlorite |
10-ppm |
12-ppm |
General Grade Hypochlorite Solution
Hypochlorite treatment chemicals shall not exceed 50% of the bromate MCL or contribute a bromate residual of 5 ppb or less to the “finished drinking water”. At the Maximum Use Level specified by NSF, the bromate in our finished products are estimated to be:
| |
Dixichlor
(Sodium Hypochlorite 10%) |
Dixichlor Max
(Sodium Hypochlorite 12.5%) |
| Maximum Use Level in Water |
105 mg/L |
84 mg/L |
| Bromate in Hypochlorite |
48-ppm |
60-ppm | |